Conventionally, there has been proposed an air conditioner, which is externally supplied with a power by an outdoor unit and able to reduce the power consumption in a standby state of an indoor unit and the outdoor unit by limiting the supply of a main power to each part via a power line in the standby state (refer to, for example, JP 2000-111123 A). The air conditioner includes the indoor unit, the outdoor unit and a signal line for transmitting and receiving a transmission signal between the indoor unit and the outdoor unit.
Since the transmission of the transmission signal via the signal line has been performed by an AC power in the conventional air conditioner, its transmission speed depends on the frequency and tends to have difficulties in being increased in speed. On the other hand, it has been concerned that, when a power supply is newly provided to increase the speed of the transmission of the transmission signal via the signal line, the power consumptions in the standby state of the indoor unit and the outdoor unit be increased due to the provision of the power supply.
Accordingly, in order to solve such a problem, the present applicant has proposed an air conditioner and a control method capable of transmitting the transmission signal at high speed and reducing the power consumption in the standby state of the indoor unit and the outdoor unit. It is noted that the air conditioner and the control method are intended for easy understanding of the present invention and neither a known art nor a prior art.
In the air conditioner, a relay is provided between one of power lines that connect the indoor unit with the outdoor unit and the signal line, and an operating power supply relay of the outdoor unit is turned on by transmitting a power for startup to the outdoor unit using the signal line by turning on the relay for a prescribed time when the operation starts from the standby state in which the power of the outdoor unit is cut off.
However, it is sometimes the case where, when the connection wires are miswired by mistake in connecting the indoor unit with the outdoor unit by connection wiring lines in the air conditioner, a closed circuit including a power source is formed between a part on the indoor unit side and a part on the outdoor unit side, and this disadvantageously leads to the damage of components.